In one aspect, this invention pertains to an olefin metathesis feedstock composition and a metathesis process therefor. More specifically, this invention pertains to an unsaturated fatty acid or fatty acid ester feedstock composition and its metathesis with a lower olefin, primarily ethylene, in the presence of a metathesis catalyst to prepare a reduced chain olefin and a reduced chain unsaturated acid or ester, preferably a reduced chain α-olefin and a reduced chain α,ω-unsaturated acid or ester.
In another aspect, this invention pertains to an integrated process involving first the metathesis of an unsaturated fatty acid or fatty acid ester feedstock composition with an olefin, preferably ethylene, to form a reduced chain unsaturated acid or ester, and thereafter, conversion of the reduced chain unsaturated acid or ester into an α,ω-hydroxy acid, α,ω-hydroxy ester, and/or an α,ω-diol. Alternatively, the reduced chain unsaturated acid or ester can be converted into an α,ω-amino acid, an α,ω-amino ester, and/or an α,ω-amino alcohol.
In yet another aspect, this invention pertains to an integrated process involving first the metathesis of an unsaturated fatty acid or fatty acid ester feedstock composition with an olefin, preferably ethylene, to form a reduced chain unsaturated acid or ester, and thereafter, conversion of the reduced chain unsaturated acid or ester into an epoxy acid or epoxy ester.
In other aspects, this invention pertains to polyester polyol, polyester polyamine, and polyester polyepoxide compositions.
Olefin (unsaturated) functionalities can be transformed into alcohol, amine, or epoxide functionalities via organic processes known in the art. In addition, monoacids and monoesters can be converted into polyesters via esterification or transesterification, respectively, with a polyol. Accordingly, unsaturated monoacids and monoesters have the potential to be converted into industrially useful polyester polyols, polyester polyamines, or polyester polyepoxides, preferably, α,ω-polyester polyols, α,ω-polyester polyamines, or α,ω-polyester polyepoxides. Polyols and polyamines find utility in the manufacture of urethane polymers. Polyepoxides find utility in the manufacture of epoxy resins. α-Olefins, by themselves, find utility in the manufacture of polyolefin polymers.
In a search for non-petroleum-based, renewable sources of industrial chemicals, recent attention has turned to various seed oils, particularly those containing a high concentration of unsaturated fatty acid esters, such as the glycerides of oleic acid. Sunflower, canola, and certain soybean oils, for example, possess concentrations of oleic acid esters in excess of 70 weight percent. It is known, for example, to transesterify seed oil fatty acid esters with a lower alcohol, e.g., C1-8 alcohol, such as methanol, to form unsaturated fatty acid esters of the lower alcohol. The latter can be metathesized with ethylene in the presence of a metathesis catalyst to form a reduced chain α-olefin and a reduced-chain α,ω-unsaturated ester. As an example, methyl oleate can be metathesized with ethylene to prepare 1-decene and methyl-9-decenoate.
WO 96/04289 discloses a metathesis process wherein methyl oleate and ethylene are contacted in the presence of a metathesis catalyst comprising a ruthenium or osmium carbene compound, such as (dichloro-3,3-diphenylvinylcarbene)-ruthenium (II), to prepare 1-decene and methyl-9-decenoate. The patent discloses a catalyst turnover number (hereinafter “turnover number”) of 143, when the process is run at room temperature and 100 psig (689 kPa) ethylene. For the purposes of this invention, the term “turnover number” shall be defined as the number of moles of unsaturated acid or ester that is metathesized, e.g., methyl oleate metathesized, per mole of catalyst.
Likewise, D. Mandelli et al. discloses in Journal of the American Oil Chemical Society, 73, no. 2 (1996), 229-232, the ethenolysis of esters of vegetable oils, e.g., methyl oleate with ethylene, over rhenium catalysts, and report a turnover number of 112. The methyl oleate is treated over alumina prior to use.
Disadvantageously, the aforementioned turnover numbers are too low to allow for commercial implementation of these metathesis processes.
M. D. Refyik et al. discloses in Journal of the American Oil Chemical Society, 76, no. 1 (1999), 93-98, that vegetable oils can be self-metathesized in the presence of Grubb's ruthenium catalyst, bis(tricyclohexylphosphine)benzylidine-ruthenium dichloride. The oils are taught to be purified over silica gel prior to use. Additional art disclosing the self-metathesis of unsaturated fatty acid esters includes purification of the unsaturated esters over silica or alumina prior to use, as reported, for example, by W. Buchowicz et al. in Journal of Molecular Catalysis A: Chemical 148 (1999), 97-103, and by P. O, Nubel et al. in Journal of Molecular Catalysis A: Chemical, 145 (1999), 323-327. A turnover number of between 650 and 2,500 is reported for methyl oleate. Disadvantageously, the metathesis of unsaturated fatty acid esters with ethylene is more problematical than the self-metathesis of unsaturated fatty acid esters. Accordingly, a significantly lower turnover number is expected when ethylene or other olefin of low molecular weight is used as a co-reactant.
C. Demes discloses in Chemosphere, 43 (2001), 39, the metathesis of methyl oleate with ethylene in the presence of a ruthenium metathesis catalyst. The process is taught to exhibit total catalyst turnover numbers of between 2,320 and 2,960 at 50° C. and 145 psi.
The implementation of integrated chemical processes derived from renewable, seed-oil feedstocks may depend significantly upon the productivity of the metathesis stage, wherein an unsaturated fatty acid or unsaturated fatty acid ester feedstock derived from seed oils is metathesized with a lower olefin, such as ethylene. Productivity can be measured, for example, by catalyst activity (e.g., conversion of unsaturated fatty acid or ester) and turnover number. Disadvantageously, prior art metathesis processes exhibit unacceptable productivity. Unless unsaturated fatty acids and esters derived from seed oils can be converted into reduced chain olefins and reduced chain unsaturated acids or esters in higher productivity, as compared with prior art processes, the integration of the metathesis process with other downstream industrially useful processes may be difficult to achieve commercially.
In view of the above, a need exists for discovery of an improved process wherein an unsaturated fatty acid or fatty acid ester feedstock composition, derived from a seed oil, is metathesized with a lower olefin, such as ethylene, to produce a reduced chain olefin and a reduced chain unsaturated acid or ester in acceptable productivity. Such a process would require a catalyst of higher activity and turnover number, as compared with prior art catalysts. Moreover, any improved process should achieve these improved results under acceptable process conditions (particularly, mild temperature and pressure and minimal diluent or solvent) and at acceptable selectivity to the desired metathesis products. A metathesis process having the aforementioned properties might beneficially be applied to converting unsaturated fatty acids and fatty acid esters derived from renewable seed oils into reduced chain olefins and reduced chain unsaturated acids and esters, preferably, reduced chain α-olefins and reduced chain α,ω-unsaturated acids and esters. Reduced chain olefins of these types could be integrated into downstream processes for preparing useful industrial chemicals, such as, polyester polyols, polyester polyamines, polyester polyepoxides, and poly(olefins).